Certain electrical connectors are to be mated to mating connectors with mating arrays of terminals thereof to become electrically engaged along connector mating faces. Where a plurality of similar such connectors are located adjacent each other in an array, for mating to a like plurality of mating connectors, the connectors must be labeled or otherwise visibly marked to indicate which of the mating connectors all similar in appearance and shape, are to mate with which of the mounted connectors all similar in appearance and shape.
It would be desirable to provide a means to mechanically prevent all but the particular mating connector from being mated to a particular connector. Types of connectors are known in which cooperating keying structures are utilized which are shaped and positioned and correspondingly oriented along the respective mating faces of the pair of connectors to allow mating when the two connectors matchingly keyed are being moved axially together, but abut and physically obstruct mating when two connectors are being moved together which are not matchingly keyed.
Such keys are usually used in pairs matable with corresponding pairs and usually have body sections which are hexagonal or (octagonal) in cross-sectional shape, and the keys of each pair are secured to a respective one of the connectors with their body sections in apertures of the connector housing which are correspondingly shaped in cross-section; thus each key can be secured in its respective aperture in any one of six (or eight) different positions, respectively. Each key includes a keying projection extending axially forwardly from the body section but only extending around about one half of the circumference; the corresponding key will have a keying projection which will enter the region comprising about the remainder of the circumference, when the two connectors which are matchingly keyed are moved axially together. The opposing keys of two otherwise matable connectors which are not matchingly keyed, will abut at their leading ends prior to at least the mating terminals of the connectors engaging. By coordinating the selection of positions of the two keys within the respective apertures of each connector of the pair desired to be matable, the keys provide a means for physically encoding the mating faces of the pair of connectors. Exemplary keys are disclosed in U.S. Pat. Nos. 4,277,126; 3,426,315; 4,159,862; 3,491,330; and 4,778,411.
Certain connectors are also known in which a pair of jackscrews are utilized to hold the connectors together in mated relationship by extending from one connector to a threaded aperture of the other along the mating face, where each jackscrew is rotatable to bring the connector mating faces assuredly together in the last stages of mating. For example, see U.S. Pat. Nos. 3,853,381; 3,573,677 and 3,112,974.
There are prior art connectors in which jackscrew hardware is assembled to the connector in conjunction with keying hardware radially surrounding portions of the jackscrews to economize on space across the mating faces on the connectors, as in U.S. Pat. Nos. 4,181,391; 3,555,491; 4,109,987 and 3,582,867.
In U.S. Pat. No. 3,555,491 polarizing members are disposed in apertures of lateral flanges of molded plastic housings and have three circumferentially spaced polarizing projections extending forwardly of the leading ends of the connector housings. A jackscrew extends through a central passageway of each member of one of the connectors and has a threaded forward shank end extending forwardly of the polarizing projections. The opposing member includes a threaded insert axially rearwardly of the projections to be threadedly engaged by the threaded jackscrew end during fastening after connector keying. Threaded engagement between the jackscrew and the insert occurs after the polarizing projections of the polarizing members have moved past each other along most of their lengths. The reference also discloses a mechanism for preventing overtorque during turning of the jackscrew, by allowing rotation of the threaded insert after a certain torque level has been reached as the connectors are completely mated. Other prior art discloses using jackscrews with polarizing hardware or assembled to serve a polarizing function include U.S. Pat. Nos. 2,902,665 and 2,746,022.
In U.S. Pat. No. 4,181,391 a connector mounted to a printed circuit board includes a key member which includes a threaded aperture rearward of the keying projection and is adapted to be threadedly engaged by a correspondingly threaded forward shank end of the jackscrew extending from a corresponding key of the mating, matchingly keyed connector. If the mating connectors were not matchingly keyed, the opposing keying projection forward ends would abut, the connectors would not mate, and the forward jackscrew end would not enter the threaded key aperture to fasten the connectors together.
It is desired to provide keying for a mating pair of connectors where the keying is adapted to be utilized with jackscrew fastener mechanisms, where it is desired that such connectors be assuredly held together by hardware, in a manner which minimizes the amount of mating face real estate occupied by the total of the keying and fastener hardware.
It is also desired to provide a means for assembling the keys and jackscrews easily and in a manner permitting easy disassembly, for facilitating assembly and disassembly at the application site in order for customizing the key orientations and permitting changing the orientations, as well as replacement of parts.
It is further desired to provide jackscrew/keying systems which are defined in a minimum number of separate parts by providing a connector shell modified to facilitate assembly.
It is yet further desired to provide jackscrew/keying systems in which the jackscrew/keying hardware and especially the jackscrew forward end are protected from damage and misalignment.